The present invention relates to a diode mixer having at least one mixer stage which receives a signal having a frequency to be converted and an oscillator signal having a preselectable oscillator frequency, wherein the mixer stage has mixer diodes arranged to be biased by a direct control voltage for the compensation of parasitic influences.
The periodical Microwave Magazine, volume 8, No. 6, 1982, page 720, discloses a mixer circuit in which direct control voltages are fed to mixer diodes in the mixer stages. With such a direct control voltage it is possible to equalize parasitic influences during the mixing process.
European Patent Application No. 44,156-A1 discloses the principle of feeding an oscillator signal derived from a frequency synthesizer to single sideband mixers.
When changing to another transmission channE1, i.e. when changing the oscillator signal, the problem arises of having to correspondingly change the biases across the mixer diodes of the mixer stages.